如何使用PHP中的imgesetthickness()函数为线条绘制设置图像厚度？

bool imagesetthickness($image, $thickness)

<?php
   // Create an image of a given size
   $img = imagecreatetruecolor(700, 300);
   $gray = imagecolorallocate($img, 0, 0, 255);
   $white = imagecolorallocate($img, 0xff, 0xff, 0xff);

   // Set the gray background color
   imagefilledrectangle($img, 0, 0, 700, 300, $gray);

   // Set the line thickness to 10
   imagesetthickness($img, 10);

   // Draw the rectangle
   imagerectangle($img, 30, 30, 200, 150, $white);
   
   // Output image to the browser
   header('Content-Type: image/png');
   imagepng($img);
   imagedestroy($img);
?>

<?php
   // Create an image of given size using imagecreatetruecolor() function
   $img = imagecreatetruecolor(700, 300);
   $blue = imagecolorallocate($img, 0, 0, 255);
   $white = imagecolorallocate($img, 0xff, 0xff, 0xff);

   // Set the white background-color
   imagefilledrectangle($img, 0, 0, 300, 200, $blue);

   // Set the line thickness to 50
   imagesetthickness($img, 50);

   // Draw the white line
   imageline($img, 50, 50, 250, 50, $white);

   // Output image to the browser
   header('Content-Type: image/png');
   imagepng($img);
   imagedestroy($img);
?>